A unified mid-gap defect model for amorphous GeTe phase change material
Applied Physics Letters
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Li, H., & Robertson, J. (2020). A unified mid-gap defect model for amorphous GeTe phase change material. Applied Physics Letters, 116 (5) https://doi.org/10.1063/1.5138998
© 2020 Author(s). Understanding the nature of the mid-gap defects in amorphous chalcogenide alloy-based phase change materials is crucial to guide the development of multi-level memories, selectors, and neuromorphic devices. Currently, however, the knowledge of the mid-gap defects is fragmented and the known structural and electrical characteristics of the defects cannot be unified in a single atomic model. In this work, a Ge-Ge chain defect model is built by artificial bond rearrangement in an amorphous GeTe network generated by atomic distortion, revealing a possible valence alternation mechanism in its formation. Atoms in the Ge-Ge chain are found to have a crystalline-like environment. The chain is found to have a negative-U property and to introduce mid-gap states. This model unifies the main known properties of the mid-gap defects in amorphous chalcogenide alloy-based phase change materials.
The authors acknowledge funding from National Natural Science Foundation (Grant No. 61974082 and 61704096) and EPSRC Grant No. EP/ P005152/1.
Engineering and Physical Sciences Research Council (EP/P005152/1)
External DOI: https://doi.org/10.1063/1.5138998
This record's URL: https://www.repository.cam.ac.uk/handle/1810/302862
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